The present invention relates generally to the simulator art, and more specifically concerns a simulation facility which provides a proper environment for testing, evaluating, and developing guidance and navigation systems which operate at radiometric frequencies.
The radiometric frequency band, as referred to herein, comprises generally the millimeter and microwave frequency ranges, covering from 18 gigahertz (gHz) to 350 gigahertz (gHz). It has been found desirable in certain applications to use the radiometric frequency band for the guidance and navigation systems on particular aircraft, missiles or other flying objects. For instance, it is known that energy propagated through the air at particular frequencies, namely 35 gHz and 94 gHz is not significantly attenuated by occluded atmospheric conditions such as fog, mist, rain, and smoke, which ordinarily interfere with most conventional guidance and navigation systems. Thus, there are known theoretical advantages to radiometric-frequency guidance systems in certain operating circumstances.
It is also known that, in certain applications, so-called passive guidance/navigation systems are more desirable than a more conventional "active" system. A passive system depends upon the energy emitted by terrain, monuments, objects, etc. for its guidance information, unlike an active system such as radar, which depends upon reflected energy for its guidance information. A passive system generally will present a more stable target for the guidance system to home on, which is important in certain applications.
A system which combines the above-described features, i.e. a passive radiometric guidance system, would appear to offer substantial operational advantages over conventional systems in particular applications. Such innovative guidance systems, however, before being introduced into real-world applications, must be thoroughly tested and evaluated. Due to the expense and unreliability of actual flight tests for operational evaluation of such systems, special-purpose simulators are usually designed and constructed for the testing and evaluation of prototype guidance systems.
The design of a simulator for testing a passive guidance system operating with radiometric frequencies, however, presents numerous technical problems, many of which are not addressed by available simulator technology.
A simulator for testing radiometric guidance systems must be capable of (1) providing a relatively quiet, or cold, background at radiometric frequencies of interest, and (2) accurately and dynamically simulating the real-world emission appearance of a terrestial scene at those same radiometric frequencies. Simulators having this capability were, to the best of the inventors' knowledge, unknown prior to the present invention.
Accordingly, it is a general object of the present invention to provide a simulation facility suitable for evaluation of guidance and navigation systems operating at radiometric frequencies.
It is another object of the present invention to provide such a device which is capable of providing a cold background at radiometric frequencies.
It is a further object of the present invention to provide such a device having the capability of accurately simulating the radiometric emission appearance of a terrestial scene, including terrain, monuments and objects.
It is an additional object of the present invention to provide such a device wherein the simulation of the terrestial scene may be changed dynamically.
It is yet another object of the present invention to provide such a device which can be constructed quickly and is relatively inexpensive.